/* ***********
 *程序：画5环，在整个屏幕不动，且居中
 *作者：周飞
 *日期：2018-7-7 
 *********/


/*  *{
	margin:0px;
	padding:0px;
 }  */

.circle {
    width: 100px;
    height: 100px;
    position: absolute;
    border-radius: 50%;
    opacity
}

.centerblack {
    border: 10px solid black;
    left: 50%;
    top: 50%;
    position: fixed;
    margin-left: -60px;
    margin-top: -85px;
}

.blue {
    border: 10px solid blue;
    right: 110px;
}

.yellow {
    border: 10px solid yellow;
    right: 50px;
    top: 50px;
}

.red {
    border: 10px solid red;
    left: 110px;
}

.green {
    border: 10px solid green;
    left: 50px;
    top: 50px;
}